Prognostic Meteorological Discussion
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FXUS02 KWBC 241600
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1159 AM EDT SUN JUL 24 2016

VALID 12Z WED JUL 27 2016 - 12Z SUN JUL 31 2016

...OVERVIEW AND GUIDANCE/UNCERTAINTY ASSESSMENT...

MODELS REMAIN IN GOOD AGREEMENT WITH THE LARGE SCALE EVOLUTION OF
FLOW OVER THE LOWER 48 LATER THIS WEEK AND THROUGH THE WEEKEND.
RIDGING IN THE WESTERN U.S. SHOULD STAY CENTERED OVER THE GREAT
BASIN...WITH THE NEXT APPROACHING UPPER TROUGH POTENTIALLY
LOWERING HEIGHTS OVER THE PACIFIC NORTHWEST AND WEST COAST BY
SATURDAY.  EAST OF THE DIVIDE...ANOMALOUS RIDGING OVER THE
MID-ATLANTIC STATES SHOULD GRADUALLY SUPPRESS INTO THE SOUTHEAST
WHILE AN UPSTREAM TROUGH SETS UP OVER THE MIDDLE/UPPER MISSISSIPPI
VALLEY AND GREAT LAKES.

THE WPC DAY 3-7 FORECAST WAS LARGELY BASED OFF ENSEMBLE MEAN
GUIDANCE...DUE TO BOTH THE LOW PREDICTABILITY WITH SMALLER SCALE
SHORTWAVE ENERGY RIPPLING THROUGH THE MEAN FLOW AS WELL AS WITH
THE INCREASING AMOUNT OF ENSEMBLE SPREAD THAT DEVELOPS WITH THE
TIMING AND AMPLITUDE OF THE NEXT UPPER TROUGH PROGRESSING INTO THE
NORTHWEST THIS UPCOMING WEEKEND.


...WEATHER HIGHLIGHTS/THREATS...

THE PATTERN SHOULD GENERALLY FAVOR AREAS OF ORGANIZED CONVECTION
FROM THE NORTHERN PLAINS INTO THE NORTHERN MID-ATLANTIC
STATES...BUT THE EXACT DETAILS OF WHERE AND HOW MUCH RAIN WILL
FALL ARE DIFFICULT TO RESOLVE IN THE MEDIUM RANGE PERIOD.  THE
COMBINATION OF MONSOONAL MOISTURE AND IMPULSES ALOFT WILL
CONTRIBUTE TO DIURNAL CONVECTION OVER THE SOUTHWEST AND
ROCKIES...WHILE FLORIDA AND LOCATIONS FROM THE CENTRAL GULF COAST
TO THE TENNESSEE VALLEY SHOULD SEE PERIODS OF SHOWERS AND
THUNDERSTORMS AS WELL.

THE WESTERN U.S. HEAT WILL EXPAND INTO THE NORTHWEST LATER THIS
WEEK...BUT THEN THE REGION SHOULD SEE A NOTICEABLE COOLING TREND
BY THE WEEKEND AS HEIGHTS LOWER WITH THE ARRIVAL OF THE NEXT UPPER
TROUGH.  MUCH OF THE EAST COAST WILL SEE ABOVE NORMAL TEMPS
MID-LATE WEEK BEFORE TEMPERATURES TREND CLOSER TO NORMAL ACROSS
THE NORTHERN HALF OF THE EASTERN U.S..  HOWEVER...PARTS OF THE SRN
MID ATLC/SOUTHEAST MAY REMAIN 5-10F ABOVE NORMAL THROUGH THE
WEEKEND.  NRN INTO CNTRL PLAINS LOCATIONS SHOULD SEE A PERIOD OF
BELOW NORMAL HIGHS WITH A WARMING TREND BY NEXT WEEKEND.


GERHARDT

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